Simulation Analysis Of Transient Slider/Discrete Track Recording Media Contacts

Ultra-high density information storage technology has become the commanding height of storage technology. Discrete track recording (DTR) media, as an effective approach to achieve higher storage density, is hopeful to attain storage density of 1Tbit/in2, therefore, has received widespread attention. During transient contacts,tracks of DTR media are so easily damaged that reliability of information storage is seriously restricted. Based on this background, this paper, by researching characteristics of DTR media during transient contacts, aims to supply theoretical guidelines for the design of DTR media which is of ultra-high reliability of information storage.In this paper,according to the rational simplified principles,finite element models of slider-DTR media contacts under different relative speeds are established. Constitutive models and theoretical thermal models are determined. Characteristics of the interaction of the transient contact thermal force field under different contact status are researched. Destruction levels of DTR media under different contact status are compared and the main factors leading to the demagnetization of the DTR media are discussed. During vertical contacts, surface friction and contact thermal field can increase the plastic strain level of DTR media. During parallel contacts, surface friction and contact thermal field have little effect on the plastic strain level of DTR media. With the same contact prerequisites, during parallel contacts, the damage extent of DTR media is more severe than that during vertical contacts. Plastic strain is the main factor that will result in the demagnetization of DTR media.The demagnetization of DTR media is mainly caused by mechanical damage. Therefore, influences of design parameters of DTR media and contact conditions on the characteristics of the transient contact force field are paid emphasized attention. First, effects of properties of different media materials under different contact status are researched with different research methods. Second, geometry parameters of models are changed in order to clarify effects of different geometry parameters of DTR media. Finally, impacts of contact conditions are investigated. During vertical contacts, reducing elastic modulus, increasing yield strength, adding DLC protective layer and increasing the thickness of DLC layer can reduce the damage level of DTR media. Increasing width of tracks,normal impact velocity and radial seeking velocity of the slider can increase the damage level of DTR media. Although increasing friction coefficient will enlarge the maximum equivalent plastic strain of DTR media, it can reduce the plastic strain region of DTR media. During parallel contacts, with the same contact prerequisites, DTR media, which is consisted of Glass substrate and CoCrPt track, has the minimum damage level. Adding DLC protective layer and increasing the thickness of DLC layer can reduce the damage level of DTR media. Increasing width of tracks can reduce the plastic region of DTR media and increase the maximum equivalent plastic strain. Increasing normal impact velocity and lateral velocity of the slider can increases the damage level of DTR media. Increasing friction coefficient can reduce the damage level of DTR media.DTR media is prone to mechanical damage. So planarization, which means grooves between different tracks are filled, has become an important research direction. The transient slider-DTR media contact model is established after planarization. First, effects of different media materials on the transient contact force field of DTR media after planarization are researched. Second, impacts of different filling materials on the transient thermal force field are investigated after the confirmation of the optimal materials of tracks and substrate of DTR media. Finally, the appropriate filling material is chosen and effects of contact conditions on the thermal force field are investigated. With the same contact prerequisites, DTR media, which is consisted of Glass substrate, CoCrPt track and CoCrPt filling material, has the minimum damage level. Increasing impact velocity and radial seeking velocity of the slider can increases the damage level of DTR media. Increasing friction coefficient can reduce the thermal-mechanical damage of DTR media and increase the maximum surface temperature of DTR media.